The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In general, a hybrid vehicle, referred to as an environmentally-friendly vehicle, is driven through a combination of two or more different power sources.
However, most of the current hybrid vehicles are driven by an engine which acquires torque by burning fuel (fossil fuel such as gasoline) and an electric motor which acquires torque using power from a battery. Hereafter, the electric motor is referred to as a drive motor.
Such a hybrid vehicle uses the mechanical energy of the engine and the electric energy of the battery together, and recovers energy through the drive motor while braking. Therefore, the fuel efficiency can be improved, and the energy can be efficiently used.
The drive motor for such a hybrid vehicle is coupled to a transmission which is a driving element of the vehicle.
That is, the drive motor is installed in a transmission housing of the transmission, and a motor housing is fastened to the transmission housing, in order to seal the transmission housing while supporting the drive motor.
The drive motor includes a stator and a rotor as main components. The stator includes a coil wound around the stator, and the rotor includes a permanent magnet inserted into a rotor core. The drive motor is driven by power received from a high-voltage battery which is mounted separately from a battery with a predetermined voltage.
The drive motor has a structure in which an inner ring of the bearing is pressed into the rotor and supported by the rotor.
Accordingly, the bearing transfers vibration to the motor housing through an outer ring of the bearing, while absorbing the centrifugal force and torque generated from the rotor.
Therefore, noise is generated by the bearing or motor housing of the drive motor.
Such a drive motor is supported by the motor housing in a state where the outer ring of the bearing is loosely fitted to the motor housing. At this time, bearing creeping may occur due to a variation in weight of the bearing ball. The bearing creeping indicates that the outer ring of the bearing has slid. Simultaneously, when the vehicle is turned to the left or right, the outer ring of the bearing is axially moved to thereby generate noise or reduce duration.
The above information disclosed in this Background section is only for enhancing the understanding of the background of the present disclosure and therefore may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.